Load Transfer System

ABSTRACT

This is a new type of pile foundation for support of structures. It uses a new method of forming concrete around the steel rebar prior to installing the rebar. Concrete is molded in an undulating fashion to improve load transfer to the adjacent hole backfill. The backfill is densified in place and grouted to maintain the dense configuration. The grouting is injected into an unlined hole. If temporary casing is used during drilling, it is removed prior to grouting. The basic premises are that grouting the hole backfill to the surrounding soil provides a better load transfer at that interface. And, beyond a few inches past the steel rebar, grouted dense sand and gravel are adequate for the load at that point. Timing of the grouting is more flexible than typical ready-mix concrete delivery systems. This method also allows for real time testing of the pile capacity.

This Application claims the benefit of U.S. Provisional Application63/204,672 Filed on Oct. 19, 2020 and U.S. Provisional Application63/234,687 Filed on Aug. 18, 2021 which are hereby incorporated intothis Patent Application.

Please note that no new specifications have been added, only minorchanges to improve the clarity of the ideas presented herein.

The standard method of constructing Cast In Drill Hole (CIDH) piles isas follows: Drill a hole in the ground based upon the projected load andthe soil/rock capacity to support the load. If caving of the holeoccurs, then install temporary casing or fill the hole with a heavierthan water drilling fluid. Next lower into the hole a steel rebar orbars tied together to form a cage. Finally fill the hole with concreteand remove the temporary casing or allow for drilling fluid to bedisplaced by the placement of the heaver concrete.

The above method has several inherent weak points that are typicallycovered by making conservative design requirements. Caving of thesurrounding soil/rock when the hole is open. The odds of this happeningincreases dramatically when the diameter is increased. There is also thedisturbed zone around the perimeter of the hole. This is from thedrilling action against the existing soil. This almost always results ina loss of strength at the critical interface between the soil and theconcrete. The hole must be sufficiently larger than the rebar cage toensure that the rebar will have a minimum cover of concrete to protectit from corrosion. There are also issues with the timing of the concreteplacement. The inspection, casing removal, and concrete pour are allperformed by different groups all working at the same time. Therefore,scheduling of each pile pour is critical. Once the concrete is mixedthere is a definite time limit on its usefulness. In summery one pilerequires the timing and close scheduling of several groups. Then if loadtesting is desired it must wait for the concrete to cure. Due to thehigh possibility of problems and the high cost of remedial repair thesepiles are typically constructed with a level of overdesign in the plansto ensure a minimum capacity pile.

Many of the above problems can be eliminated or minimized if the rebaris first covered with a minimum protective cover of concrete that has anundulating shape. The advantage to the undulating shape is that coveredrebar will perform well when transferring load to or from lower strengthmaterial.

The attached figures listed here show how this will work:

FIG. 1 Cut view of section of pile in hole showing transfer of externalload to soil.

FIG. 2 Cut view of complete pile with modified rebar transferring loadto soil.

FIG. 3 Cut view of multiple piles for moment frame to provide temporarystabilization.

FIG. 4 Enlarged perspective view of moment frame system.

FIG. 5 Cut view of multiple piles with modified rebar for permanentground stabilization.

FIG. 6 Cut view of multiple piles forming a gravity wall in existingsoil.

FIG. 7 Cut view of common fill gravity wall system for comparison withFIG. 6.

FIG. 8 Perspective view of trench stabilization using modified rebar andrandom fill.

FIG. 9 Perspective view of multiple stabilization trenches prior toexcavation.

FIG. 10 Perspective view of FIG. 9 after vertical cut is complete.

FIG. 11 Cut view of alternate method to the modified rebar system.

FIG. 12 Two rebar that will become an alternate system of nodes totransfer load.

FIG. 13 Cut view of multiple bent rebar forming node using FIG. 12design.

The claim of this patent is if the order of the CIDH pile constructionis changed the above listed problems can be eliminated or minimized. Thebasic idea is to cover the steel rebar with an undulating coating ofconcrete prior as shown in FIG. 1 to placing into the hole. This ensuresthat each rebar has the minimum concrete cover. The rebar is loweredinto the hole along with the grout/water pipes and the vibratoryequipment. This is shown on FIG. 1 the rebar 1_is shown inside the borehole with limits 9. The process in FIG. 1 has reached the grouting phaseas demonstrated by the grout 13 flowing out of the grout pipe 11. Sand 7and gravel 6 have been densifies by the vibrator 12. FIG. 2 presents asection view of a modified rebar 1 in a piles hole that is filled withsand 7 gravel 6 and grout_13. FIG. 2 also shows how the load 3 istransferred from the rebar 1 to the molded concrete 2 through loadtransfer 14 along the ribs of the rebar. Then the load is transferredfrom the concrete to the sand 7 and gravel 6 that will be grouted 13 toimprove its load carrying capacity. Then the load is transferred 15 fromthe pile_to the grouted soil 10. The soil 10 has been improved where thegrout 8 has intruded. Leaving the hole unlined or the casing removedincreases the likely hood that the weakest layers in the soil 10 will beimproved by allowing the grout to flow freely. It should be noted thateither during or after backfilling filling the hole the same pipes 11can be used to wet the granular material and the vibratory device 12 candensify the material to ensure proper load transfer from the coatedrebar to the foundation soil beyond the hole. To complete the processliquid grout 13 would then be injected into the hole. Grouting has twopurposes; 1) the grout will lock the sand and gravel in place tomaintain its high-density configuration, and 2) under pressure the groutwill. flow out into the surrounding soil. Filling the majority of thehole with granular material and grouting changes the interface 9_into agradual change from one soil type to another. This would greatly improvethe contact between the drilled hole and the supporting soil 10formation. Which is the primary limiting factor when determining thepile's capacity. This is typically described as the adhesion factorbetween dissimilar materials such as soil/steel and soil/concrete.

The ground improvement and grouting industry have developed a largenumber of grouting materials. This includes what is known as “granddaddygrout”. That is a simple mixture of water and Portland cement andpossibly fly ash to help it flow. The choice of grout and/or granularfill is not a subject of this patent application. The system proposedherein will work with a wide verity of grout and granular fill material.The choice of those materials for any given project would depend uponmany factors such as desired load capacity, cost, and availability ofmaterials.

It is helpful to look at the basic aspects of how a CIDH pile functions.The Youngs modulus of the steel is so large compared to the concrete, orthe modulus of the soil that it carries all of the load initially.Moving down the pile the load is transferred to the concrete whichultimately transfers it to the soil. This compressive load transferinside the concrete is primarily through the gravel portion of theconcrete mix. This is why densification of wet concrete is so important.The individual gravels must be in contact with the adjacent gravel. Thenat the foundation soil/concrete interface the load must be transferredfrom the outer surface of the concrete to the soil which has beendisturbed by the drilling process.

Examination of the load transfer finds that the high strength of theconcrete is only utilized at the steel rebar/concrete interface. As theload moves out away from the rebar it becomes spread out over a largerand larger area. Thus, the same load is carried by a larger volume ofconcrete. This results in lower and lower levels of stress per unit ofconcrete. The end result is that the majority of the concrete isunderutilized, and its primary function is to be filler material. FIG. 2again shows that the lower pressure can be carried by sand 7 and gravel6 zone where they are locked by grout 8 in a dense configuration. Thissystem will work just as efficiently as typical as a CIDH pile.

For concrete the primary purpose of the sand and cement is to hold thegravel size rock in-place. Therefore, a similar product can be producedby first installing dense sand and gravel and then injecting a cementingor grouting agent under pressure. The primary limitation to this “out oforder process” is the stress level at the rebar to concrete interfacewhere load transfer 14 occures. The ribs on the rebar are intended towork with wet concrete forming around them. This can be overcome bypouring concrete around the rebar and allowing it to harden prior toinstalling the rebar in the pile hole. At this point in the process thekey to successful load transfer is provided by the shape of theconcrete. Tests to date indicate that if the concrete is molded in anundulating shape there is very good load transfer between the concreteand the dense sand and gravel material used to finish filling the hole.

It has become obvious that the majority of the concrete in a CIDH pileis underutilized. Once the load has been transferred from the steel tothe concrete then a lower strength filler material such as dense sandand gravel that is grouted in place will suffice. Therefore, thegrouting process results in a superior overall product because itimproves the pile to soil contact. Given the variable nature of naturalsoil formations it is essential that all casing be removed prior togrouting. This is to ensure that the grout will encounter and improveall weak layers along the pile/soil interface.

Given the tendency for grout to travel out into the soil beyond thelimit of the drilled hole the end result is a pile that functions likeit is larger than the initial drill size of the hole. Thus, a smalldiameter pile could have the same capacity as a larger pile. FIGS. 3 and4 present a condition where small diameter piles would have a greatadvantage over typical CIDH piles. The fact that the grout will extendbeyond drilled hole allows for greater spacing in shoring piles. Also,for temporary conditions the molded concrete 2 could be designed suchthat the steel rebar 1 can be removed and reused when the excavation hasbeen backfilled, and the steel is no longer needed. The details of howthat can be accomplishes will be discussed in the detailed descriptionof the Figures. The primary claim of this patent is that unstable groundconditions can be stabilized by this method of load transfer usingmodified steel rebar 1.

For a permanent stabilization project FIG. 5 shows how modified rebar 1in grouted 8 holes 17 can be configured to form the equivalent of agravity retaining wall. This is accomplished by tying the piles togetherwith a concrete slab 23 at the top of the wall so that the soil 10 isnow a single mass described in the detailed figure description of FIG. 6and FIG. 7. The FIG. 7 shows a typical method for building a gravitywall using horizontal ties 30 in a new compacted fill 29. This method ofconstruction requires a large amount of earth moving to make the backcut 28, and typically the new compacted fill 29 needs to be imported dueto the fact that the horizontal reinforcement 30 only works withspecific soil types. FIG. 6 shows the same gravity wall constructed fromthe top down prior to the excavation of the original ground suggested byline 27. For this method to work the load created by the excavationneeds to be absorbed by the upper section of the piles and transferredto stable ground at a lower elevation.

Another use for the modified rebar 1 with its undulating concrete cover2 is presented on FIG. 8, FIG. 9, and FIG. 10. Here the modified rebar_1is placed horizontally or close to horizontal in a trench. Then thetrench is backfilled to or close to the original ground surface. Thenthe fill mass around the modified rebar 1 can be grouted using the groutpipes 11 that were placed within the fill. The fill mass could includecobble and boulder size rocks 32 and/or demolition concrete 33. Thesewould be placed in a matrix of sand 7 and gravel 6. It is this granularsoil matrix that will be grouted into a solid mass. This solid mass isheld together by the modified rebar 1 which will carry tensil load. Thatload is transferred from the surrounding soil 10 through the groutedfill mass to the undulating concrete 2 to the rebar 1. This isessentially how steel reinforced concrete works. The difference withthis is the overall load is small enough that strength of concrete isonly needed around and along the steel rebar 1. FIG. 9 shows the line 34of the proposed vertical cut. The advantage to grouting the fill is thatthe grout will also penetrate adjacent soil 10. This will make a betterconnection between the soil 10 and the grouted fill trench that is heldtogether by the steel rebar. The back section of the trench will act asan anchor where it is contact with stable soil 10.

FIG. 10 shows the condition where the vertical cut 39 is complete. Whenvertical cuts are made the soil 10 behind the face moves down and outinto the cut ground. With properly spaced filled trenches the movementof the soil 10 out of the vertical cut 39 will be prevented as thetrenches will act as anchors. In addition to the trenches FIG. 10presents the possibility of drilled and filled piles 17 that willtransfer the load to deeper stable soil 10. For this condition the loadon the wall face supporting cut 39 is minimal.

For the purpose of making a load transfer system it is not necessary touse concrete nodes on the rebar. Where the corrosion of the rebar is nota concern then the nodes could be fashioned by making spiral shapedrebar around the central load bearing steel. FIG. 11 shows spiral rebarwelded to a central tube. The central tube could be used to transmit thegrout 13 through holes 38. Also, the tube could transmit and transferthe load 3 to the spiral shaped rebar. The load would be transferredfrom the spiral rebar to the grouted gravel and then to the surroundingsoils along a path shown as the arrow 4. Again, the load transfer isimproved by grout 8 penetrating the soil 10. Another method simpler thanspiral shaped nodes is bent small diameter rebar 36 laid alongside theload bearing rebar 1 as shown on FIG. 12. When grouped together theyform a node as shown on FIG. 13. This figure shows a node where insidethe rebar is a net to hold the gravel 6 inside the node. As with theother nodes the remainder of the fill is held in-place by grout 13delivered by grout tube 11. The end result is load 3 is transferred tothe node rebar 36 and ultimately through the gravel along the arrow 4.

-   The following provides a more in-depth description of the enclosed    figures. These figures and the descriptions here in are intended to    provide a novel approach to transferring load from one zone of soil    that needs support to a stable zone located close by. As with other    existing methods this design relies upon steel rebar to carry most    of the load. The difference with this approach is to use a minimal    volume of concrete that can be applied any_time prior to the use of    the rebar 1. The advantage is that the grout can be applied at any    time and if it has a short set time then it can be load tested    quickly to ensure that it will function as designed. When Portland    cement concrete is used it typically develops the majority of its    strength over a period of weeks.

FIGURES

FIG. 1

This figure shows the basic design and operation of the modified rebar.This shows the undulating concrete molded 2 around two adjacent rebar 1.It should be noted that the modification claimed herein is not limitedto concrete. Other variations are covered later in this submittal. Whatis claimed as that it is necessary for the covering to have anundulating shape. As shown, where more than one rebar 1 is required theundulating shapes 2 can be aligned out of phase to improve theconnectivity. This configuration is also a way for two rebar 1 to bespliced together. The load 3 is delivered to the system through therebar 1. Said load is then transferred from the rebar 1 to the moldedconcrete 2 by friction 14 along the ribs of the rebar 1. Load is thentransferred out of the molded concrete 2 primarily across the slopingface 5 of the undulation. The sloping face 5 will transfer the load tothe adjacent material. The adjacent material may be another concretemold 2, gravel 6, sand 7, or solid grout 8. The load passes throughseveral mediums to reach the edge of the boring 9. At that point likewith all other cast in drill hole piles the load is transferred to thesurrounding soil 10. Following the principal of physics, that thestiffest element carries the vast majority of the load. In this casethat would be the densified gravel 6. The primary purpose of the sand 7and solid grout 8 are to hold the gravel 6 in place. This is why theorder of construction is important. First the saturated sand 7 andgravel 6 are vibrated into a dense configuration. Then the liquid grout13 is injected to lock the dense sand 7 and gravel 6 into place. This isdone by first injecting water into the filled boring through the pipe 11and vibrating the sand 7 and gravel 6 into a dense configuration. Thiscan be accomplished using a typical concrete vibrator 12. As the wet mixof sand 7 and gravel 6 become dense then the vibrator 12 is withdrawn.Depending upon site conditions pipe 11 could be used to withdraw, excesswater from the boring. Once the sand 7 and gravel 6 are in a denseconfiguration the liquid grout 13 can be injected primarily to lock thesand 7 and gravel 6 into place. Because the boring is not lined or casedthe grout 13 will seep out beyond the edge of the boring 9. This willimprove the contact and load transfer at the interface between the edgeof boring 9 and the surrounding soil 10. Once the liquid grout 13 hasflowed to its limit it will solidify into solid grout 8. This completesthe load transfer process from load 3 to the surrounding soil 10. Aswill be shown in additional figures it is possible to reverse this loadtransfer process from surrounding soil 10 that needs support. The weightof soil 10 can be transferred to rebar 1 which will carry it as load 3to a depth where it can be transferred back to a soil 10 layer that canprovide support.

FIG. 2

This figure shows a completed pile that is subject to an external load3. The grout pipes 11 are left behind after the piles has beencompleted. As shown the load is transferred from the rebar 1 to the node2 along the ribs of the rebar 1. From there it passes through thematerial of the node 2 to the dense sand 7 and gravel 6, that is lockedin place by the solid grout 8. This is shown by the arrows 4 where thesloping face 5 is placing a compression load of the dense sand 7 andgravel 6. The load then is delivered to the surrounding soil 10 whichhas been improved by the solid grout 8. Because the hole is unlined atthe time that the liquid grout 13 is injected into the system it is freeto flow into the weakest zones of the surrounding soil 10. This actionof improving the weakest zones causes the overall strength of thesurrounding soil 10 to be improved. As discussed above the weakestinterface between a pile 17 and the supporting medium is at the edge ofthe pile 9. Leaving the pile unlined provides the greatest possibilitythat this interface will be improved.

FIG. 3

This figure shows how these piles could be used to support a temporaryexcavation. By tying the piles together, a moment frame can beconstructed. Unlike the pile presented in FIG. 2 these piles are notsubjected to structural vertical load at the top of the pile. Insteadthe soil provides the load as the excavation is made. The removal oflateral support during the excavation causes adjacent soil to move downand into the excavation. This generates soil load 15 at the soil/pileinterface. Unless there is an anomaly in the surrounding soil 10creating a dominant plane of weakness, the natural initial movement isdown along a steep failure plane. This is what generates the soil load15. This results in a vertical load being placed on the dense grouted 8sand 7 and gravel 6 of the pile. This same load 15 is then transferredas a compression load 19 primarily at the up facing sides 18 of theundulating node 2. From there the load is transferred to the steel rebar1 at the interface 14 between concrete node 2 and the rebar 1. Themethod of pile construction described herein would be particularly welladapted to provide support for this condition. This is due to thegrouting 8 of the soil and the shape of the undulating nodes. The load15 is now carried by the stiffest element, that is the rebar 1 down tothe supported soil 10 where it is transferred from rebar 1 to concretenode 2 to dense sand 7, gravel 6 and grout 8. From there across thepile/soil interface 9 to the surrounding soil 10. This vertical supportof the soil along with lateral support provided by the multiple pilemoment frame 20 will greatly reduce the load on temporary shoring. Fortemporary shoring the rebar 1 could be threaded rebar which if placed ina sleeve prior to forming the nodes would be removable when the projectis complete. Given the vertical capacity of the piles, this wouldimprove the excavations shoring ability to support traffic load close tothe excavation. The main intent is to create a safe working conditionfor installing a utility 21, which typically require a deeper excavationto make room for the sand bedding 22.

FIG. 4

This is a close up showing a moment frame 23 that ties two piles 17together. The rebar 1 shown are threaded which also can function asbolts to help attach the moment frame 23 to the piles 17. The drawingalso shows a cut away view of the pile 17. It should be noted that thepiles 17 as shown are not complete or ready for service as the groutingis not complete.

FIG. 5

This shows another use for this pile 17 system. Using multiple rows ofpiles 17 can result in the formation of a gravity retaining wall. At thepresent time gravity walls are built from the bottom of a temporaryexcavation using select compacted fill with horizontal ties. That methoduses the solid mass of the reinforced fill to hold the remaining soilin-place. The method proposed herein claims that by using numerous smallpiles 17 that provide vertical support to the existing soil 10 the soilclosest to a proposed cut or retaining wall will function the same as agravity wall. Thus, the soil 10 closest to the cut or wall thattypically requires support is now self-supporting. The piles 17 haveturned the problem into the solution. Given that these piles are notlarge enough to be soldier piles they do need to be tied together tofunction as a unit. Given that the entire rebar 1 does not need to becovered with nodes 2 makes it possible to use the upper part of therebar 1 to tie the piles 17 together. This system of tying the piles 17together could be either a concrete slab or grade beams 24. The sameslab or grade beam system 24 could also be used to help support the wallface 25 by tying the wall rebar 1 to the pile 17 rebar 1. With the soil10 self-supporting the wall 25 only needs to provide erosion control.Also, the wall 25 needs to support the sand 7 fill above the back drain26.

FIG. 6

This shows an idealized section of a gravity wall created by installingpiles 17 in close formation as discussed in FIG. 5. As described in FIG.5 the piles 17 need to be installed prior to making the excavation forthe retaining wall 25. A typical original ground surface 27 is shown infront of the retaining wall 25. The vertical piles 17 have created agravity wall within the boundary line 26. The vertical soil 10 load istransferred to the deeper soil 10 below line 26. This system eliminatesthe need for excavation and backfill with reinforced select fill soil.

FIG. 7

This shows the typical excavation and reinforced fill soil 29 for theconstruction of a gravity wall. The excavation removes the soil 10 tothe back cut limit 28, which is very similar to the gravity wallboundary line 26 in FIG. 6. The manufactures of the fill soilreinforcing strips 30 have developed methods to calculate the proper andsafe back cut limit 28. This determines the size and volume of the fillsoil 29 and the length and vertical spacing of the fill soil reinforcingstrips 30. What is claimed here is that stabilizing the existing soil 10would require piles 17 to support and unify the soil 10 into semisolidmass that will function as a gravity retaining wall. The primaryadvantage of using piles 17 is that it does not require the mass gradingand earth moving needed for the method outlined in FIG. 7.

FIG. 8

Given that the rebar 1 is modified by shaping nodes 2 around the rebarprior to its use allows for other uses. FIG. 8 shows a perspective viewof a backfilled trench with a cut way section to show the inside of thetrench. The purpose of the trench is to improve the overall stability ofthe existing soil 10 around the trench. In this embodiment the rebar 1modified with nodes 2 have been placed horizontally in the trench as itwas backfilled. The backfill could include inert demolition debris 33along with sand 7 and gravel 6 fill. As the trench is backfilled groutpipes 11 are inserted in the fill. During, or at the completion oftrench 31 filling water and vibratory equipment can be used to densifythe fill. The grout pipes 11 could be used for water injection. During,or at the completion of trench filling liquid grout 13 can be injectedinto the densified mix of debris 33, sand 7 and gravel 6. The purpose isfor grout 8 to fill the void spaces between the debris 33, sand 7 andgravel 6 and flow out beyond the trench 31 to tie the soil 10 to thetrench 31. The overall process is to create a rebar 1 reinforced slot inthe ground with the minimum excavating and earthmoving.

FIG. 9

This figure shows a continuous level soil 10 surface where a proposedexcavation 34 is planned. To improve the stability of the proposedexcavation 34 trenches 31 have been excavated perpendicular to thealignment of line 34. It should be noted that the alignment of thetrenches 31 does not require them to be perpendicular to the proposedexcavation 34. This depiction of the modified rebar 1, and the fill isin the process of backfill trenches 31. It should be noted that themodified rebar 1 can be laid in the partially filled trench 31 at anangle, if a horizontal alignment is not desired. Where needed piles 17can be added to improve the stability of the backcut soil 10 that willremain after the excavation 34 is mad along the dashed line.

FIG. 10

This figure shows the completed excavation supported by filled andgrouted trenches 31 reinforced by rebar 1 covered by nodes 2. The soil10 along the cut face line 34 is supported horizontally by the filledtrenches 31 and vertically by the piles 17. For analyses purposes, thestability of a typical cut is a two-dimensional analysis. The advantageof this condition is the stability analysis is now a three-dimensionalanalysis with filled trenches 31 providing additional stability to theoverall cut slope. For localized stability piles 17 can be added alongthe cut 34 between the trenches 31.

FIG. 11

This presents a different method of creating a node 2 along a rebar 1.As shown the center rebar has been replaced with an injection pipe 11.Two or more small rebar 36 are bent to form a spiral around the centerpipe 11. These smaller rebar 36 are attached to the pipe 11 by welding37. In this embodiment the grout pipe 11 serves two purposes. First, itis the method of providing water or grout and with multiple injectionholes 38 that can be closed off using a method known as a tube-amanchette system. Second the pipe 11 is sufficient to support axel load3. The load 3 is transferred to the small bent rebar 36 through the weld37. The spiral shape is filled with gravel 6 which extends beyond thespiral bent rebar 36. The gravel 6 is densified and locked into place bythe solid grout 8 that was originally injected into pile 17 through theinjection hole 38. Again, the slope of the bends in the small rebar 36impart a portion of the original load 3 to the gravel 6 in the form of acompression load 4. The grouted 8 gravel 6 transmits the compressionload 4 through the gravel 6 to the surrounding soil 10. The interfacealong edge of the drilled hole 9 is improved by the gravel 6 beingdensified and pushed into the surrounding soil 10. What is clamed hereinis that all of the load transfer systems described in FIGS. 1 through 10can also be done using the spiral rebar 36 and the modified injectionpipe 11.

FIG. 12

This figure shows two rebars. On is a strait rebar 1 and the second is asmaller bent rebar 36. The purpose of this figure is to show how a node2 can be made using standard rebars. The node 2 requires several ofthese bent rebars 36 attached to the strait rebar 1. If the attachmentis done by welding then the strength of the strait rebar 1 may bereduced. However, analyses should be performed to determine how muchload an individual node 2 would be transferred from rebar 1 to the soil10.

FIG. 13

This figure shows a group of small bent rebar 36 form a node 2 aroundthe primary rebar 1. This system would have a node 2 filled with gravel6 which are held in place by a screen. Similar to the previous node 2systems described in FIGS. 1 through 10 this node would also be held inplace by grout 8. The load 3 is transferred from the main rebar 1 to thesmaller bent rebar 36.

The rebar 36 transfers the load to both the gravel 6 inside the node 2and the pile 17 gravel 6 fill. The load is disseminated through thegravel 6 to the soil 10. The load transfer is improved by the densifiedgravel 6 pressed into the soil 10 and possible grout 8 intrusion intothe soil 10. What is clamed herein is that all of the load transfersystems described in FIGS. 1 through 10 can also be done using the bentrebar 36 system to form a node 2.

1. First claim of this application is that the pile will function thesame if the concrete is only placed around the rebar for a few inches,and the remainder of the hole is filled with dense sand and gravel. Dueto the lower stress level as discussed above the grout locking the densesand and gravel in-place does not need to be as strong as Portlandcement. The other advantage to grout is a quick set time allows forreal-time testing to ensure the load capacity of the pile. What isnecessary is to mold the concrete in an undulating fashion so that thesloping surface places a compressive load on the dense sand and gravel.Second claim is the grout will penetrate the surrounding soil thusgiving the pile the capacity of a larger diameter then the drill size ofthe hole. The amount of penetration is dependent upon the soil conditionand the type of grout that is being used. Third claim The load transferprocess described herein works just as well in reverse. The transfer ofload from soil to steel rebar is just as efficient as load going fromrebar to foundation soil. This load transfer makes it possible tosupport soil where lateral support soil is being removed. This commonlyoccurs with temporary or permanent excavations. If the soil adjacent tothe proposed cut is first vertically supported then the cut is stablebecause the supported soil has become a gravity wall. Fourth claim usingmultiple piles drilled and set in an area adjacent to a proposed cut fora retaining wall will result in lower load on the wall. This is due tothe grouted piles providing vertical support for the soil adjacent tothe cut. Vertical support for the soil adjacent to the cut reduces oreliminates the driving force that creates the load on the retainingwall, temporary shoring. In the case of temporary shoring it is possibleto use threaded rebar and mold the concrete around a threaded sleeve.Once the temporary excavation is backfilled the threaded rebar can beunscrewed from the shoring pile and reused. Fifth claim The same loadtransfer system can be accomplished using smaller bent rebar attachedand around the main load carrying rebar. Two examples of this type ofsystem are provided herein. One uses small rebar twisted to form aspiral node and the other uses multiple bent rebar to form a node. Themain advantage to these systems are they can be formed on site usingstandard rebar and be put into use immediately.